Method of extending color life of modified atmosphere packaged fresh red meat using labiatae plant extracts

ABSTRACT

The color life of modified atmosphere packaged fresh red meat is extended by contacting the fresh red meat with an extract of a  Labiatae  herb prior to packaging the meat.

FIELD OF THE INVENTION

This invention relates to a method for extending the color life ofmodified atmosphere packaged fresh red meat, and more particularly, to amethod of extending the color life of modified atmosphere packaged freshred meat using extracts of Labiatae plants.

BACKGROUND OF THE INVENTION

It has been a desire for major meat manufacturers to supply retailoutlets from centralized processing facilities. In order to facilitatethis desire, modified atmosphere packaged fresh meats have beendeveloped. Modified atmosphere packaging, also known as MAP, of freshmeats involves the use of specific gas mixtures in the headspace of gasimpermeable meat containers and enables the control of certain physicalproperties, such as appearance, of the fresh meats for an extendedperiod of time.

Color shelf life of red meat is important to consumer acceptance.Consumers judge the freshness of red meat by the presence of bright redoxymyoglobin pigment. Oxymyoglobin in fresh red meat decreases with timeduring storage as it changes to the stable brown pigment, metmyoglobin.Although oxymyoglobin pigment fades during dark storage, for example ina meat locker, pigment loss is most pronounced in lighted, refrigerateddisplay cases in retail establishments. Although pigment loss isprimarily cosmetic in nature, it has serious economic consequences.Consumers in search of the freshest looking cuts avoid purchasing redmeat containing even small amounts of brown metmyoglobin. The unsaleableproduct which results from oxymyoglobin loss in red meats costs theindustry an estimated $700 million dollars annually.

Modified atmosphere packaging can be divided into two categories, highoxygen modified atmosphere packaging having an oxygen content above 40vol. % and low oxygen modified atmosphere packaging having an oxygencontent less than 20 vol. %. In low oxygen modified atmospherepackaging, oxygen is excluded from the package and the headspaceatmosphere is usually made up of an inert gas such as nitrogen or amixture of nitrogen and carbon dioxide. With low oxygen MAP,oxymyoglobin initially present on the surface of the meat is convertedto deep purple, unnatural appearing, deoxymyoglobin pigment as the lastremnants of oxygen are consumed by metabolic processes occurring in themeat tissue.

Deoxymyoglobin is a fairly stable pigment under completely anoxicconditions although it can convert to metmyoglobin during storage. Whenoxygen is re-introduced to the meat containing deoxymyoglobin, the meatre-blooms as deoxymyoglobin is converted back into oxymyoglobin. Thisphenomena has been used by meat companies with so-called “peel-pack”packaging in which the meat is packaged in a tray covered by two,separate plastic films, an outer oxygen barrier film and an inner oxygenpermeable film. The meat is transported and stored under anoxicconditions and, prior to display in the retail meat case, the outer filmis removed to allow the meat to re-bloom and re-form the bright redpigment, oxymyoglobin, consumers expect to see. The use of “peel-pack”technology has not been embraced commercially because of the handlingnecessary to remove the oxygen barrier film from each package and theneed to insure adequate bloom time prior to display in the retail case.The meat industry is seeking a packaging technology that can be producedat the manufacturing point, distributed and displayed at retailfacilities with a minimum of handling.

In high oxygen modified atmosphere packaging, high oxygen levels aremaintained in the headspace atmosphere from the time of packagingthrough the time of consumption. Mixtures of oxygen and carbon dioxideare typically used, with a gas mixture of 80% oxygen and 20% carbondioxide being most typical. The high oxygen helps extend the microbialshelf life of the product by inhibiting the growth of anaerobicmicroorganisms, many of which are pathogens.

With both types of MAP, gas mixtures are used with carbon dioxideplaying a significant functional role and other gases, particularlynitrogen, functioning as optional inert diluents. Carbon dioxide ispresent in the gas mixtures because at sufficient levels, it is toxic tocertain bacteria and thereby enhances the product's shelf life.

Modified atmosphere packaging has provided a method of extending thefavorable appearance and properties of fresh meat but there still is aneed for a method of further extending the packaged appearance of freshmeats.

W. Manu-Tawiah, L. L. Ammann, J. G. Sebranek and R. A. Molins, 1991.“Extending the Color Stability and Shelf Life of Fresh Meat,” FoodTechnology 45(3), 94-102, teach that mixtures of tetrasodiumpyrophosphate, sodium erythrobate and citric acid combined with modifiedatmosphere storage extended the color life of various meat types andcuts. The headspace atmosphere used in this work was 50% CO₂, 15% O₂ &35% N₂. Pork chops, beef rib steaks, and ground beef samples wereexamined. Treatment suspensions were applied by marination of prime cutsand by direct addition to ground beef prior to the final grind. Sampleswere stored at 2° C. in cardboard boxes for 0, 7, 14, 21, or 28 daysprior to opening. After master batch storage, individual trays werestored at 2° C. under fluorescent light for 0, 2, 4, 6, 8, or 10 days.Very little effect was seen on pork. Ground beef showed the mostimprovement with shelf life being extended by 1-3 days. In contrast,steaks gained one day of shelf life while no improvement was seen forchops. The greatest color differences occurred after 7 days dark storageand 3 days storage in the light. Erythrobate was shown to havesignificant effects on color in beef and to effect TBAs favorably.Sensory panelists were unable to distinguish between treated anduntreated materials at any stage.

C. Faustman, W. K. M. Chan, M. P. Lynch and S. T. Joo, 1996, “Strategiesfor Increasing Oxidative Stability of (Fresh) Meat Color.” ReciprocalMeat Conference Proceedings, 49, 73-79 teach that adding water solubleantioxidants such as ascorbic acid to meat preserves red meat color.Oxymyoglobin is more stable in meat with higher tocopherolconcentrations. This work did not involve MAP technology. The authorsalso reviewed work showing that modified atmosphere packaging was aneffective tool for extending color life. These authors showed that meatstored in MAP which contained sachets of iron (an oxygen scavenger)demonstrated significantly greater retail color shelf life than thosewhich were not exposed to oxygen scavengers.

S. D. Shivas, H. H. Kropf, M. C. Hunt, M. C. Kastner, L. L. A. Kendalland D. A. Dayton, 1984. “Effect of Ascorbic Acid on Display Life ofGround Beef,” J. Food Protect. 47, 11-15, 19, disclosed that ascorbicacid levels at 0.05 and 0.1% prolonged display life of 20 and 25% fatgrade ground beef, with 25% fat content beef giving higher scores. Beefflavor improved with ascorbic acid treatment while TBA values decreasedwith ascorbic acid treatment. Display life was extended by 5 days. Thiswork did not involve MAP technology.

B. E. Greene, I.-M. Hsin and M. W. Zipser 1971, “Retardation ofOxidative Color Changes in Raw Ground Beef.” J. Food Sci. 36, 940-942,treated ground beef with ascorbic acid plus either BHA or propylgallate. Treatment was shown to effectively retard oxidation for up toeight days of refrigerated storage. This work did not involve MAPtechnology.

Chin S. Cheng, U.S. Pat. No. 4,683,139, Jul. 28, 1987, teaches a processfor preserving color in fresh pork using a phosphate, ascorbic acid oriso-ascorbic acid and a chelator (EDTA, citric or tartaric acid) incombination with modified atmosphere packaging. The treatment extendedcolor shelf life up to 21 days. The atmosphere used in this work rangedfrom about 2% to about 30% oxygen.

T. Okayama 1987, “Effect of Modified Gas Atmosphere Packaging After DipTreatment on Myoglobin and Lipid Oxidation of Beef Steaks.” Meat Sci.19, 179-185 dipped beef steaks in an ethanolic solution of ascorbic acidand tocopherol. The MAP (80% O₂, 20% CO₂) steaks with or without diptreatment maintained acceptable color after 13 days of storage. Diptreatment showed no significant improvement in color. TBA numbers ofsamples stored in air or under 80% O₂, 20% CO₂ atmosphere were lower forthe dip treated samples than for the non-dip treated samples.

Allen, P., Doherty, A. M., Buckley, D. J., Kerry, J., O′Grady, M. N.,Monahan, F. J. 1996, “Effect of oxygen scavengers and vitamin Esupplementation on colour stability of MAP beef,” 42^(nd) In. Cong. MeatSci. Technol., 88-89, teaches that supplementation of the diet of steerswith 2000 units of vitamin E (tocopherol) per day for forty days priorto slaughter had no effect on color stability of steaks stored with orwithout iron-containing oxygen scavengers in an atmosphere of 50% carbondioxide; 50% nitrogen.

Sante, V., Renerre, M., Lacourt, A., J. Food Qual. 17 177-195, discussesthe effect of modified atmosphere packaging on color stability and onmicrobiology of turkey breast meat. The best color results were obtainedusing a 100% carbon dioxide atmosphere combined with an oxygenscavenger. This treatment outperformed atmospheres containing highlevels of oxygen.

J. H. Hotchkiss et al, “Advances in and Aspects of Modified AtmospherePackaging in Fresh Red Meats”, Reciprocal Meat Conf. Proc. 42 (1989),pages 31-40, states that although rosemary has been added to MAP poultryto preserve the color thereof, “Fortunately for the poultry people,poultry is not judged for myoglobin, so color is not a serious problem.”

Yukichi Kimura et al, U.S. Pat. No. 4,380,506, Apr. 19, 1983, disclosesthe addition of extracts of herbs such as sage, rosemary, marjoram,thyme, oregano and basil to food products such as ham, sausage andprocessed marine and livestock products for their antioxidant andanti-bacterial properties.

Uy Nguyen et al, U.S. Pat. No. 5,017,397, May 21, 1991, discloses plantextracts which are obtained by supercritical fluid extraction of groundleaves of the Labiatae family and added to food products such asprocessed meats and fish for their antioxidant properties. They do notdiscuss red meats.

Paul H. Todd, Jr., U.S. Pat. Nos. 5,061,403 and 5,209,870, Oct. 29, 1991and May 11, 1993, both disclose a process for preparing an alkalinesolution of Labiatae antioxidants and the use of these antioxidants incombination with polyphates in the pumping or brining of meats toinhibit “warmed-over” flavor and prevent off-color development.

Souzan Saad Latif Abd. El-Allm et al, Culinary herbs inhibit lipidoxidation in raw and cooked minced meat patties during storage”, J SciFood Agric (1999), Vol. 79, pages 277-285, disclose the mixing of spiceextracts, such as sage, basil, thyme and ginger, with ground porkpretreated with an aqueous salt solution to prevent lipid oxidation.

F. Timmermann, “Effectiveness of Natural Antioxidants in Salami-typeSausages”, Oils-Fats-Lipids (1975), Vol. 2, pages 351-353, discloses theuse of natural antioxidants such as tocopherols or spice extracts inprolonging the shelf life of animal fats and cured raw sausages.

Although the prior art discussed above shows different methods ofreducing oxidation effects in meats, particularly in the presence ofoxygen scavengers and in inert atmospheres, this work is directedprimarily at cured meats, or fresh red meat packaged under low (<30%)oxygen containing atmospheres. Only one author, Okayama, examined freshred meat stored under a high oxygen, atmosphere and his dip treatmentwas found to be ineffective in improving color. The prior art does notadequately address the problem of color retention in fresh red meats,and the need for a safe, permissible, and effective method of extendingcolor life of prepackaged red meats remains. There still exists a needfor a method of greatly extending the color life of modified atmospherepackaged fresh red meat, including meat that has not been subjected to achemical processing or pretreatment step, through the use of a naturaltreating agent. While the prior art used oxygen scavengers such asascorbates and erythrobates to prolong color shelf life, these are notpermissible additives to red meats. The combination of these scavengerswith conventional antioxidants, such as the synthetics BHA and BHT, andtocopherol, would be expected to slow down lipid oxidation. However,none of these conventional lipid antioxidants are permissible additivesin red meats. Consequently, this invention provides the only presentlyknown legal means of extending the color shelf life of MAP red meats.

SUMMARY OF THE INVENTION

A method of extending the color life of fresh red meat packaged in anelevated oxygen atmosphere comprising a step of contacting fresh redmeat with an extract of a Labiatae herb prior to packaging the meat.

It is a further object of the present invention to provide red meatpackaged in an atmosphere of greater than about 40% oxygen andcontaining an extract of a Labiatae herb.

These and other objects of the present invention are accomplished bycontacting fresh red meat with an extract of a Labiatae plant prior tosubjecting the meat to modified atmosphere packaging.

In one embodiment of the present invention, the Labiatae plant extractis applied to the fresh red meat by spraying.

In a preferred embodiment of the present invention, the fresh red meatis contacted with a rosemary extract prior to subjecting the meat tomodified atmosphere packaging.

DETAILED DESCRIPTION

For the purposes of this invention, “fresh red meat” is red meat thathas not been subjected to a curing process to alter the characteristicsof the meat and includes meat from cattle, deer, goats, buffalo, elk andswine.

Labiatae plants contain a number of phenolic compounds that can functionas food antioxidants. The compounds have different solubilitycharacteristics depending on their structure and extracts can beprepared which contain predominantly lipophilic or hydrophilic phenoliccomponents. One skilled in the art will be able to effect the propercombination to achieve the greatest possible effect at an acceptabledose. It should be recognized that many of the potentially activeconstituents are presently unknown. While rosemary is the preferredherb, sage, oregano, thyme and mints also are preferred members of theLabiatae genus.

Extracts can be prepared by using solvents in a manner conventionallyused to prepare spice oleoresins extracts and infusions. Solvents caninclude those approved under 21 CFR part 173, such as water, ethanol,methanol, isopropyl alcohol, ethyl acetate, hexane, acetone, methylethyl ketone, methylene chloride, dichloroethane or mixtures thereof, oradditionally, fluorohydrocarbons alone or in combination with food gradesolvents. They can also be prepared by extraction with supercriticalfluids such as supercritical carbon dioxide. Fluids which function assolubilizers or carriers can be added to the ground spice prior to thepressing operation. Suitable extraction methods are disclosed in U.S.Pat. Nos. 4,380,506, 5,017,397, 5,061,403 and 5,209,870, the disclosuresof which are hereby incorporated by reference.

Lipophilic extracts can be prepared by extracting the dehydrated, groundspice in a food grade solvent such as hexane, acetone, or mixtures ofhexane and acetone. Ethyl acetate or other food approved, relativelynon-polar solvents, or mixtures of these solvents can also be used inthis process. Active charcoal can be added to the ground spice prior toextraction or to the miscella after extraction to reduce chlorophylllevels in the resultant extract. After extraction, the solvents areremoved by vacuum distillation and reduced to below FDA regulatedlevels. The resulting extracts are diluted with soybean oil to provideoil-dispersible or lipophilic final products with standardizedperformance in stabilizing test oils. For rosemary and other Labiatae,these extracts contain the lipid-soluble portion of the spice, and caninclude carnosic acid and carnosol and other as yet unidentified activecomponents. Optionally, food grade emulsifying agents such as lecithin,hydroxylated lecithin, monoglycerides, diglycerides, polysorbates,diacetyl tartaric acid esters of monoglycerides, and the like, ormixtures thereof can be added as carriers or diluents.

Hydrophilic extracts can be prepared by a two stage extraction process.The dehydrated, ground spice is first extracted with a mixture of hexaneand acetone. The solid residue from the extraction is then re-extractedusing a mixture of acetone and water, methanol and water, ethanol andwater or isopropyl alcohol and water. The resulting miscella issubjected to vacuum distillation to remove the solvent. It canoptionally be purified by partitioning between water and an organicsolvent. The final aqueous mixture may be diluted with food gradepropylene glycol or glycerin to make a standardized, hydrophilicproduct. For rosemary, oregano, mint and other spices, these extractscontain hydrophilic components including rosmarinic acid. The use ofaqueous alkaline solution are not contemplated for use in the methodsand products of this invention.

Dispersible extracts containing both lipophilic and hydrophiliccomponents can be prepared by extracting the dehydrated, ground spice(optionally containing active charcoal) with a mixture of methanol andwater, ethanol and water, isopropyl alcohol and water or acetone andwater. After solvent removal, the concentrated extract can be dilutedwith a vegetable oil or with propylene glycol to provide anoil-dispersible or water-dispersible extract, respectively. Optionally,food grade emulsifying agents such as lecithin, hydroxylated lecithin,monoglycerides, diglycerides, polysorbates, diacetyl tartaric acidesters of monoglycerides, and the like, or mixtures thereof can be addedas carriers.

Labiatae herbs of two or more species can be combined and extracted toyield a product that can be used to enhance the color life of red meatstored in high oxygen atmospheres. Alternatively, extracts preparedseparately from two or more Labiatae herbs can be combined and are auseful part of this invention.

The extracts used in the present invention can either be in the form ofboth lipophilic and hydrophilic preparations or mixtures thereof.

Ground rosemary can be extracted with a number of food grade solvents ormixtures thereof, such as hexane, acetone, methanol, ethanol, ethylacetate, or with supercritical carbon dioxide. Depending upon thepolarity of the solvent or solvent mixture different constituents can beextracted. Non-polar solvents favor the lipophilic components. Polarsolvents favor the hydrophilic components. Some solvents extract bothcomponents and these can be partitioned in subsequent steps if desired.

After extraction, the solvents are removed by distillation to residuallevels that meet FDA regulations. Active charcoal can be added atseveral points in the process to remove chlorophyll. The charcoalcontaining adsorbed chlorophyll is removed by filtration. Some volatileoils can be removed by distillation to control flavor. Vegetable oil canbe added to the lipophilic extracts as a standardizing agent. Food gradeemulsifiers can be added in place of vegetable oils to make waterdispersible forms of the rosemary extract. Polar, hydrophilic food gradematerials such as propylene glycol or glycerine or alcohol can be addedto the hydrophilic extracts to standardize the flavor and activity.These extracts are well known in commerce under the common name ofoleoresins.

Oleoresin rosemary containing the more lipophilic phenolic ingredients,such as carnosic acid and carnosol, which are specially prepared to havechlorophyll removed therefrom, can be applied directly by a sprayingprocess onto the surface of the meat. The oleoresin can be diluted witha vegetable oil in order to facilitate the spraying thereof. Theeffective dosage or coating amount generally ranges from about 1 to 40grams of oleoresin per 20 pounds of meat but can be varied as thesituation dictates. A more preferred dosage amount is from 0.025 to 1wt. % based on the total weight of the meat.

The water-dispersible forms of the rosemary extracts are rosemaryoleoresins containing food-grade emulsifiers such as polysorbates, monoand diglycerides, lecithin, hydroxylated lecithin, sorbitan esters,tartaric acid esters of mono- and di-glycerides. These preparations arebest used by combining them with up to 10 times, or more, of theirweight of water, or brine, and applying the resulting suspension inamounts ranging from about 20 to 180 grams per 20 pounds of meat. Thedilution rate of the water-dispersible rosemary extract can be adjusteddepending on the process.

The hydrophilic rosemary extracts have been found to be particularlyeffective in stabilizing the meat color in modified atmosphere packagedred meats. A solution of rosmarinic acid and water or a mixture of waterand a food grade alcoholic solvent, such as propylene glycol, has beenfound to be particularly convenient to apply. In one method ofapplication, a propylene glycol/water solution containing approximately3.2 weight percent rosmarinic acid is diluted by a factor of ten inwater and sprayed onto the meat in an amount of about 10 to 120 grams ofdiluted solution per 20 pounds of meat prior to packaging.

It is desirable to have the lipophilic extract present in an amount of100-5000 ppm, preferably 500-2000 ppm, based upon meat weight. Thehydrophilic extract is preferably present in treated red meat in anamount of from 50-5000 ppm, preferably 500-4000 ppm. If carnosic acid ispresent in the extract, it should be contained in the treated red meatin an amount of from 5-300 ppm, preferably 10-50 ppm and if rosmarinicacid is present in the extract, it should be contained in the treatedred meat in an amount of from 5-300 ppm, preferably 20-120 ppm. Therange of dosages of the extracts which can be employed is very widebecause the extracts themselves can be prepared in ways which providegreatly increased or decreased concentrations of the active components.Much smaller dosages of the highly concentrated extracts can providefunctional amounts of the active components in the final meat product.It is noted, however, that using higher doses of extracts which are moredilute in active components often confers the advantage of providing amore uniform and therefore more effective dispersion of the dose in thefinal meat product. The concentrations and doses can be adjusted on acase by case basis by one skilled in the art to provide the optimumperformance.

The present invention can be practiced by spraying techniques such asthe utilization of pneumatic sprayers, electrostatic sprayers andatomizers to incorporate the extract onto the meat. Other techniquessuch as painting, dipping, marinating, vacuum tumbling injecting, mixingand pumping can also be used to incorporate the extract into the meat.The inventive mixtures can also be combined with and mixed into groundmeat during the grinding process or at some point thereafter. Theinventive mixtures can be combined with other additives such aspolyphosphates, salt, water, flavors, broths, added proteins, sugar,starches and the like which are commonly incorporated into meats. Highlywater-dispersible compositions formulated with emulsifying agents areparticularly suited for this use.

It is important to distinguish fresh meats which may contain theseingredients and are covered by the present invention from cured meats,which may contain the same ingredients, but also contain one or more ofthe following: erythorbates, erythorbic acid, ascorbates, ascorbic acid,nitrites, nitrates or cultures. The present invention is limited tofresh meats, and does not include the stabilization of meat color incured meats. The pigments in cured meat are chemically different fromthose in fresh red meat which makes them more stable. The inventivemixtures can be applied to a carrier such as maltodextrin, salt,texturized soy protein and the like. These solid dispersions can in turnbe added to the meat by mixing or grinding. Combinations of theseapplication techniques will sometimes be advantageous. It is also withinthe scope of the present invention to combine the Labiatae extracts withother naturally occurring antioxidants to stabilize the color of themodified atmosphere packaged meats. That is, it is contemplated that theLabiatae extracts can be combined with at least one of tocopherols,tocotrienols, green tea extracts and citric acid, should these becomepermissible additives. Additionally, mixtures of the hydrophilic andlipophilic Labiatae extracts can be used in the treatment of the meatprior to it being packaged. The specific ratios and dosages of thehydrophilic Labiatae extracts to the lipophilic extracts in the mixturecan readily be determined by one skilled in the art to provide optimumperformance depending on the meat and packaging conditions. It is alsowithin the scope of the present invention to combine the Labiataeextracts with flavorings in the form of spice extracts such as blackpepper, celery, white pepper, garlic and onion or synthetic flavoringssuch as reaction flavors and glutamates.

The advantages of the present invention are illustrated by the followingexamples. Up to three meat sources were blended to achieve the desiredfat contents. Coarse ground, vacuum packaged ground chuck or roundcontaining from 14-19% fat was obtained in 14 pound chubs from a localmeat company. Lean meat from whole chuck pectoral muscle (approximately10% fat) was obtained from the same source. Meat removed from beef trimfrom the same source contained 45% fat. These meat feedstocks werepre-ground through a 3/16 inch plate to reduce their particle size andaid in subsequent blending. The lean and fat portions were weighed into12 pound batches in appropriate relative amounts to give the desired fatcontent and blended for two minutes in a Mainca RM-35 meatmixer/blender. Paddle direction was reversed every 15 seconds during thetwo minute blending time. Where a color-stabilizing treatment was added,one half of the required amount was added initially and the remainderadded after 30 seconds of blending. Dry ice, crushed to a particle sizeof less than 1.7 mm, was added to maintain the meat temperature between28 and 32 degrees Fahrenheit during blending. The meat was then groundthrough a ⅛ inch plate and separated into one pound samples. The groundmeat was packaged into Cryovac BT92 trays using an Ilpra Basic 100 VGsingle mold modified atmosphere packaging machine using a barrier film.A heat seal temperature of 110° C. and heat seat time of 4 seconds wasused. The packages were evacuated using a 700 mm Hg vacuum and backflushed with a +30 mm Hg stream of the appropriate gas mixture.

Headspace oxygen and carbon dioxide levels were measured with a PBIDansensor Checkmate 9000 analyzer. C.I.E. 1976 L*a*b* values wereobtained using a Minolta CR-300 Chroma meter using the “C” light sourceand multi measure reading (average of three successive readings). Threereadings across the diagonal of the package were taken and averaged. Thepackaging film was cut away from the tray and flattened against the meatprior to the color measurements and the readings were taken through thefilm. The CIE Lab color measurement system defines a three dimensionalcolor space in which values L*, a* and b* are plotted at right angles toeach other. L* is a measure along an axis representing lightness ordarkness. A measure along a red/green axis gives a* and a measureagainst a yellow/blue axis is represented by b*. CIE Lab is a popularcolor space for use in measuring reflective and transmissive objects.The a* value is widely used in the meat industry as a measure ofredness. The time necessary for a sample to lose one third of its colorhas been arbitrarily chosen as a point at which to compare varioustreatments. A loss of more than one third of its color may be acceptableunder some commercial conditions.

For the studies of combined dark and light storage, the meat was storedat a temperature of 32-35 degrees F. in the dark for ten days and thenplaced in a light box capable of providing uniform light of 200 footcandles (cool white fluorescent lamps) at a temperature of 35-40 deg. F.Under incandescent light, color loss is slower.

EXAMPLES

The following Examples demonstrate that the combination of high (>40%)oxygen modified atmosphere packaging combined with a rosemary or otherLabiatae extract will extend color life to a commercially viable lengthof time. The dosages and relative amounts of hydrophilic and lipophilicconstituents can be ascertained by techniques described herein by oneskilled in the art. They will vary with the fat content, the freshnessof the meat, the type of animal and even the strain, and with thefeeding prior to slaughter.

Example 1

Ground beef containing 85% lean and 15% fat was prepared according tothe method described above. The standardized lipophilic rosemary extractwas added to the meat at a dose of 0.1% by weight based upon total meatweight and provided about 20 ppm carnosic acid to the final meatproduct. The standardized hydrophilic extract was added to the meat at adose of 0.1% by weight based upon total meat weight and provided about32 ppm rosmarinic acid to the final meat product. The meat was packed inoxygen-impermeable packaging under an atmosphere of 70 vol. % oxygen and30 vol. % carbon dioxide. The meat was stored in the dark at atemperature of 32 degrees F. for 26 days. Samples were pulled at days 3,5, 7, 10, 12, 14, 16, 18, 20, 22 and 26. The redness of the meat wasmeasured colorimetrically using a* values. The percent a* retained wasplotted vs. time in days. From these curves, the time at which eachsample had faded to ⅔ of its original a* value (⅓ a* loss) wasdetermined. A level of ⅔ of the starting color is commerciallyacceptable and is used as a cutoff point herein. In this test, groundbeef containing no additive (control) was compared to ground beefcontaining a lipophilic rosemary extract and to a sample of ground beefcontaining a hydrophilic rosemary extract. Table 1 shows the daysrequired for each sample to lose ⅓ of its a* value.

TABLE 1 Days to ⅔ Percentage Additive Original a* Value Change Control 6— Lipophilic 10 167% Rosemary Extract Hydrophilic 13 216% RosemaryExtract

The samples containing lipophilic or hydrophilic extracts show dramaticincreases in color stability as measured by retention of a* values.

Example 2

Ground beef containing 75% lean and 25% fat was prepared according tothe method described above. The standardized hydrophilic extract wasadded to the meat at a dose of 0.1% by weight based upon total meatweight and provided about 32 ppm rosmarinic acid to the final meatproduct. Samples of the meat were packed in oxygen-impermeable packagingunder various mixtures of oxygen and carbon dioxide. The meat was storedunder cool white fluorescent lights at 200 foot candles at a temperatureof 35-40 degrees F. Samples were pulled at daily intervals for six daysand the redness of the meat was measured colorimetrically using a*values. The percent a* retained was plotted vs. time in days. From thesecurves, the time at which each sample had faded to ⅔ of its original a*value (⅓ a* loss) was determined. In this test, ground beef containingno additive (control) was compared to ground beef containing ahydrophilic rosemary extract. Table 2 shows the days required for eachsample to lose ⅓ of its a* value.

TABLE 2 Days to ⅔ Additive Original a* Value Percent Change Control 3 —(80% O₂; 20% CO₂) Hydrophilic 4.5 150% Rosemary Extract (80% O₂; 20%CO₂) Control 2.2 — (70% O₂; 30% CO₂) Hydrophilic 4.5 205% RosemaryExtract (70% O₂; 30% CO₂) Control 2.4 — (40% O₂; 60% CO₂) Hydrophilic2.6 108% Rosemary Extract (40% O₂; 60% CO₂)

The improvement seen is more substantial for higher oxygen atmospheresthan for meat packaged in a 40% oxygen, 60% carbon dioxide atmosphere.Meat loses color much more rapidly under fluorescent lighting than inthe dark. The hydrophilic rosemary is effective in preventinglight-induced color loss in ground beef.

Example 3

Ground beef containing 75% lean and 25% fat was prepared according tothe method described above. The standardized lipophilic rosemary extractwas added to the meat at a dose of 0.1% by weight based upon total meatweight and provided about 10 ppm carnosic acid to the final meatproduct. Samples of the meat were packed in oxygen-impermeable packagingunder various mixtures of oxygen and carbon dioxide. The meat was storedunder cool white fluorescent lights at 200 foot candles at a temperatureof 35-40 degrees F. Samples were pulled at daily intervals for six daysand the redness of the meat was measured colorimetrically using a*values. The percent a* retained was plotted vs. time in days. From thesecurves, the time at which each sample had faded to ⅔ of its original a*value (⅓ a* loss) was determined. In this test, ground beef containingno additive (control) was compared to ground beef containing alipophilic rosemary extract. Table 3 shows the days required for eachsample to lose ⅓ of its a* value.

TABLE 3 Days to ⅔ Percent Change Additive Original a* Value (increase)Control 3 — (80% O₂; 20% CO₂) Lipophilic 3.3 110% Rosemary Extract (80%O₂; 20% CO₂) Control 2.2 — (70% O₂; 30% CO₂) Lipophilic 3.5 159%Rosemary Extract (70% O₂; 30% CO₂) Control 2.4 — (40% O₂; 60% CO₂)Lipophilic 2.8 117% Rosemary Extract (40% O₂; 60% CO₂)

Example 4

Ground beef containing varying fat to lean ratios were preparedaccording to the method described above. The standardized hydrophilicrosemary extract added at 0.1% by weight provided 32 ppm rosmarinic acidto the final meat product. The standardized hydrophilic rosemary extractadded at 0.4% by weight provided 128 ppm rosmarinic acid to the finalmeat product. The standardized hydrophilic oregano extract added at 0.2%provided 64 ppm rosmarinic acid to the final meat product. Samples ofthe meat were packed in oxygen-impermeable packaging under an atmosphereof 70 vol. % oxygen and 30 vol. % carbon dioxide. The meat was storedfor 10 days in the dark at 32 degrees F. and then placed under coolwhite fluorescent lights at 200 foot candles at a temperature of 35-40degrees F. Samples were pulled after ten day's storage and at dailyintervals thereafter for testing. The percent a* retained was plottedvs. time in days. In this test, ground beef containing no additive(control) was compared to ground beef containing hydrophilic rosemaryextract. Table 4 shows percent a* values retained at various times.

TABLE 4 % a* Retained Day 10 % a* retained (% Increase 10 days dark +Additive over control) 2 days Light Control 42 33 (75% lean, 25% fat)0.1% Hydrophilic 74 64 rosemary (176%) (194%) 75% lean, 25% fat 0.4%Hydrophilic 79 68 rosemary (188%) (206%) 75% lean, 25% fat Control 60 55(82% lean, 18% fat) 0.1% Hydrophilic 87 66 rosemary (145%) (120%) 82%lean, 18% fat Control 58 38 (85% lean, 15% fat) 0.1% Hydrophilic 71 57rosemary (122%) (150%) 85% lean, 15% fat 0.2% Hydrophilic 68 58 oregano(117%) (153%) 85% lean, 15% fat

Meat producers are looking for acceptable color after 10 days storage inthe dark followed by 2 days storage in the light. The border betweenacceptable and unacceptable color is dependent upon the observer, but isaround an a* value of 17. This corresponds in these studies to about ⅓loss of beginning a* value. Therefore, a retained a* value >67% after 10days dark storage and 2 days in the light would be deemed of realcommercial value. None of the control samples were able to achieve thislevel of color retention. It should be noted that the meat used in thisexample was perhaps 4-6 days old when purchased. Better performance isexpected if the rosemary extracts are added to fresher meat after only aday or two old.

Example 5

Ground beef containing varying fat to lean ratios were preparedaccording to the method described above. The dispersible extract wasformulated to contain hydroxylated lecithin and diacetyltartaric acidesters of monoglycerides as emulsifying agents. The dispersible extractadded at 0.1% by weight provided about 10 ppm carnosic acid and about 5ppm rosmarinic acid to the final meat product. The lipophilic rosemaryextract added at 0.1% by weight provided about 10 ppm carnosic acid tothe final meat product. Samples of the meat were packed inoxygen-impermeable packaging under an atmosphere of 70 vol. % oxygen and30 vol. % carbon dioxide. The meat was stored for 10 days in the dark at32 degrees F., and then placed under cool white fluorescent lights at200 foot candles at a temperature of 35-40 degrees F. Samples werepulled after ten day's storage and at daily intervals thereafter fortesting. The percent a* retained was plotted vs. time in days. In thistest, ground beef containing no additive (control) was compared toground beef containing a lipophilic rosemary extract. Table 5 showspercent a* values retained at various times.

TABLE 5 % a* Retained Day 10 % a* retained (% Increase 10 days dark +Additive over control) 2 days light Control 42 33 (75% lean, 25% fat)0.1% Lipophilic 62 49 rosemary (148%) (148%) 75% lean, 25% fat 0.1%Dispersible 70 55 rosemary (167%) (167%) 75% lean, 25% fat Control 58 38(85% lean, 15% fat) 0.1% Lipophilic 64 44 rosemary (110%) (116%) 85%lean, 15% fatWhile the percent a* retained in this Example is less than the desired67%, the example demonstrates that effectiveness can be improved byformulating the extract into a dispersible form, and that the dosagemust be increased as the fat content of the meat decreases.

Example 6

Ground beef containing 82% lean and 18% fat was prepared according tothe method described above. The standardized hydrophilic rosemaryextract added at 0.1% by weight provided 32 ppm rosmarinic acid to thefinal meat product. Samples of the meat were packed inoxygen-impermeable packaging under atmospheres of 80 vol. %

oxygen and 20 vol. % carbon dioxide; 70 vol. % oxygen and 30 vol. %carbon dioxide and air (21 vol. % oxygen, 0% carbon dioxide). The meatwas stored for 10 days in the dark at 32 degrees F., and then placedunder cool white fluorescent lights at 200 foot candles at a temperatureof 35-40 degrees F. Samples were pulled after ten day's storage and atdaily intervals thereafter for testing. The percent a* retained wasplotted vs. time in days. In this test, ground beef containing noadditive (control) was compared to ground beef containing a hydrophilicrosemary extract. Table 6 shows percent a* values retained at varioustimes.

TABLE 6 % a* Retained Day 10 % a* retained (% Increase 10 days dark +Additive over control) 2 days light Control 55 29 AIR 0.1% Hydrophilic61 28 rosemary (111%)  (97%) Air Control 60 55 (70% O₂; 30% CO₂) 0.1%Hydrophilic 87 66 rosemary (145%) (120%) 70% O₂; 30% CO₂ Control 79 49(80% O₂; 20% CO₂) 0.1% Hydrophilic 87 64 rosemary (110%) (131%) 80% O₂;20% CO₂

While both treatments provide acceptable color retention, this exampleshows that 70% oxygen is sometimes superior to 80%. The optimum oxygencontent therefore must be ascertained on a case by case basis. It isnoted that none of the packages containing an atmosphere of air hadacceptable shelf life, demonstrating the significance of elevated oxygencontent.

The treatment of the red meat according to the present invention priorto the modified atmospheric packaging unexpectedly greatly extends thecolor life of the red meat. The Labiatae extract is preferably added tothe meat prior to grinding and is effective under high oxygenconditions. When the red meat is treated with hydrophilic rosemaryextract and packaged in a modified atmosphere containing 70 vol. %oxygen and 30 vol. % carbon dioxide, the color life of the red meat hasits greatest extension. Additionally, the present invention can be usedto extend the color life of whole muscle cuts of meat as well as groundmeat under similar processing and packaging conditions as ground meat.

The lipophilic extracts used in the above examples were standardized togive a dose of 10-20 ppm carnosic acid at a 0.1% dose of extract. Thehydrophilic extracts used in the above examples were standardized togive a dose of 32-128 ppm rosmarinic acid at a 0.1-0.4% dose of extract.Dosages of carnosic acid in the finished meat product can vary between 5and 300 ppm, depending on the storage and lighting conditions, and thedesired shelf life. Under most conditions, optimum dosages will be inthe range of 10 to 50 ppm. Dosages of rosmarinic acid in the finishedmeat product can vary between 5 and 300 ppm, depending on the storageand lighting conditions, and the desired shelf life. Under mostconditions, optimum dosages will be in the range of 20 to 120 ppm.Combinations of lipophilic and hydrophilic constituents generally willreduce the dosage of the individual constituents or significantlyincrease color life. Up to about 300 ppm carnosic acid and up to about300 ppm rosmarinic acid are feasible combinations. The optimum dose willdepend upon the condition of the meat, the fat content, the desired MAPoxygen concentration, as well as the amount of other active constituentsin the individual extracts. The relative amount of active constituentsin the Labiatae genus varies from species to species. It can bedetermined by analytical procedures known to the art, such as highperformance liquid chromatography (HPLC). In general, oxygen should begreater than 40% of the headspace, preferably greater than 60% and mostpreferably in the range of 70% to 80%, with carbon dioxide constitutingthe balance. A portion of the carbon dioxide can be replaced with aninert gas filler such as nitrogen or argon. Those practicing the artwill be able to optimize dosages and mixtures of constituents and gasesfor specific meat applications. While the specification shows methods ofextending the color shelf life by several days, an extension of only oneday is commercially advantageous and may be achieved in art byregulating the dose.

It is to be understood that the invention is not to be limited to theexact details of operation, or to the exact compositions, methods,procedures or embodiments shown and described above, as obviousmodifications and equivalents will be apparent to one of ordinary skillin the art, and the invention is only limited by the full scope legallyaccorded the appended claims.

1. A high oxygen modified atmosphere package comprising a fresh red meatproduct in an atmosphere of greater than about 40% oxygen and whereinsaid fresh red meat contains a hydrophilic extract of a Labiatae herb inan amount sufficient to extend the color life of the fresh red meatproduct, wherein the extract contains rosmarinic acid, is free of someof its volatile oils and has high antioxidant activity and littleantimicrobial activity in fresh red meat.
 2. The high oxygen modifiedatmosphere package claim 1 wherein the treated meat contains betweenabout 5 and about 300 ppm rosmarinic acid.
 3. The high oxygen modifiedatmosphere package of claim 1, comprising a fresh red meat product in anatmosphere of greater than about 60% oxygen and wherein said fresh redmeat contains a hydrophilic extract of a Labiatae herb in an amountsufficient to extend the color life of the fresh red meat product,wherein the extract contains rosmarinic acid, is free of some of itsvolatile oils and has high antioxidant activity and little antimicrobialactivity in fresh red meat.
 4. A high oxygen modified atmosphere packagecomprising a fresh red meat product in an atmosphere of greater thanabout 40% oxygen and wherein said fresh red meat contains a lipophilicextract of a Labiatae herb in an amount sufficient to extend the colorlife of the fresh red meat product, wherein the extract containscarnosic acid and optionally carnosol, is free of some of its volatileoils and has high antioxidant activity and little antimicrobial activityin fresh red meat.
 5. The high oxygen modified atmosphere package ofclaim 4, wherein the treated meat contains between about 7.5 and about300 ppm carnosic acid.
 6. The high oxygen modified atmosphere package ofclaim 4, comprising a fresh red meat product in an atmosphere of greaterthan about 60% oxygen and wherein said fresh red meat contains alipophilic extract of a Labiatae herb in an amount sufficient to extendthe color life of the fresh red meat product, wherein the extractcontains carnosic acid and optionally carnosol, is free of some of itsvolatile oils and has high antioxidant activity and little antimicrobialactivity in fresh red meat.
 7. A high oxygen modified atmosphere packagecomprising a fresh red meat product in an atmosphere of greater thanabout 40% oxygen and wherein said fresh meat contains an extract of aLabiatae herb in an amount sufficient to extend the color life of thefresh red meat product, wherein the extract contains both hydrophilicand lipophilic constituents, selected from the group consisting ofcarnosic acid and rosmarinic acid is free of some of its volatile oilsand has high antioxidant activity and little antimicrobial activity infresh red meat.
 8. The high oxygen modified atmosphere package of claim7, wherein the treated meat contains between about 7.5 and 300 ppmcarnosic acid and between about 5 and 300 ppm rosmarinic acid.
 9. Thehigh oxygen modified atmosphere package of claim 7, comprising a freshred meat product in an atmosphere of greater than about 60% oxygen andwherein said fresh meat contains an extract of a Labiatae herb in anamount sufficient to extend the color life of the fresh red meatproduct, wherein the extract contains both hydrophilic and lipophilicconstituents, selected from carnosic acid and rosmarinic acid, and isfree of some of its volatile oils and has high antioxidant activity andlittle antimicrobial activity in fresh red meat.